Weak Measurements of Light Chirality with a Plasmonic Slit

We examine, both experimentally and theoretically, an interaction of tightly focused polarized light with a slit on a metal surface supporting plasmon-polariton modes. Remarkably, this simple system can be highly sensitive to the polarization of the incident light and offers a perfect quantum-weak-measurement tool with a built-in post-selection in the plasmon-polariton mode. We observe the plasmonic spin Hall effect in both coordinate and momentum spaces which is interpreted as weak measurements of the helicity of light with real and imaginary weak values determined by the input polarization. Our experiment combines advantages of (i) quantum weak measurements, (ii) near-field plasmonic systems, and (iii) high-numerical aperture microscopy in employing spin-orbit interaction of light and probing light chirality.Comment: 5 pages, 3 figure

Particle trapping and beaming using a 3D nanotip excited with a plasmonic vortex

Recent advances in nanotechnology have prompted the need for tools to accurately and noninvasively manipulate individual nano-objects. Among the possible strategies, optical forces have been widely used to enable nano-optical tweezers capable of trapping or moving a specimen with unprecedented accuracy. Here, we propose an architecture consisting of a nanotip excited with a plasmonic vortex enabling effective dynamic control of nanoparticles in three dimensions. The structure illuminated by a beam with angular momentum can generate an optical field that can be used to manipulate single dielectric nanoparticles. We demonstrate that it is possible to stably trap or push the particle from specific points, thus enabling a new, to the best of our knowledge, platform for nanoparticle manipulation. (C) 2020 Optical Society of Americ

Almost Sure Frequency Independence of the Dimension of the Spectrum of Sturmian Hamiltonians

We consider the spectrum of discrete Schr\"odinger operators with Sturmian potentials and show that for sufficiently large coupling, its Hausdorff dimension and its upper box counting dimension are the same for Lebesgue almost every value of the frequency.Comment: 12 pages, to appear in Commun. Math. Phy

Coriolis Effect in Optics: Unified Geometric Phase and Spin-Hall Effect

We examine the spin-orbit coupling effects that appear when a wave carrying intrinsic angular momentum interacts with a medium. The Berry phase is shown to be a manifestation of the Coriolis effect in a non-inertial reference frame attached to the wave. In the most general case, when both the direction of propagation and the state of the wave are varied, the phase is given by a simple expression that unifies the spin redirection Berry phase and the Pancharatnam--Berry phase. The theory is supported by the experiment demonstrating the spin-orbit coupling of electromagnetic waves via a surface plasmon nano-structure. The measurements verify the unified geometric phase, demonstrated by the observed polarization-dependent shift (spin-Hall effect) of the waves.Comment: 4 pages, 3 figure

Path connectedness and entropy density of the space of hyperbolic ergodic measures

We show that the space of hyperbolic ergodic measures of a given index supported on an isolated homoclinic class is path connected and entropy dense provided that any two hyperbolic periodic points in this class are ho-moclinically related. As a corollary we obtain that the closure of this space is also path connected

Helical light emission from plasmonic vortices via magnetic tapered tip

We investigate an architecture where a plasmonic vortex excited in a gold surface propagates on an adiabatically tapered magnetic tip and detaches to the far-field while carrying a well-defined optical angular momentum. We analyze the out-coming light and show that, despite generally high losses of flat magnetic surface, our 3D structure exhibits high energy throughput. Moreover, we show that once a magneto-optical activity is activated inside the magnetic tip a modulation of the total power transmittance is possible

Helicity locking of chiral light emitted from a plasmonic nanotaper

Surface plasmon waves carry an intrinsic transverse spin, which is locked to its propagation direction. Apparently, when a singular plasmonic mode is guided on a conic surface this spin-locking may lead to a strong circular polarization of the far-field emission. Specifically, a plasmonic vortex excited on a flat metal surface propagates on an adiabatically tapered gold nanocone where the mode accelerates and finally beams out from the tip apex. The helicity of this beam is shown to be single-handed and stems solely from the transverse spin-locking of the helical plasmonic wave-front. We present a simple geometric model that fully predicts the emerging light spin in our system. Finally, we experimentally demonstrate the helicity-locking phenomenon by using accurately fabricated nanostructures and confirm the results with the model and numerical data